there is no voltage potential in the molten bath. If molten metal were to touchthe coil, the ground leak detectorprobe will conduct current from the coil to ground. This will be detected by the ground detector module and the powerwill be shut offto stop any coil arching. This also prevents high voltage from being carried bythe molten metal or furnace charge. Such high voltage could cause serious or even fatal electrical shock to the operator if he were to come into conductive contact with the bath. (As a normal safety precaution, powerto the furnace always should be turned off during slagging, sampling and measuring).
Ground Detector Module turns off power
The ground leak detector probe works in conjunction with the ground detector module mounted inside or external to the power supply. This module automatically turns off power to the furnace if any improper ground is detected in the induction coil. This is crucial to furnace safety. If the furnace refractory lining or crucible cracks or otherwise fails and a portion of the metal bath touches the energised furnace coil, the coil could arc and rupture. This could allow water to get into the bath, causing metal eruption or explosion. Both parts of the system, the ground probe and the ground leak detector, must function properly for safe melting operations.
Systen Maintenance Probe
To keep the ground leak detector probe working properly in a rammed lining furnace, care must be taken when installing the lining to insure that the ground leak detector probe wires come into contact with the lining form. Also, when patching a furnace lining, it is essential that the ground leak detector probe wires remain exposed, permitting contact with the furnace charge.If the wires are too short, extra lengths of 305 stainless steel wire should be weldedto the existing wires to extend the wires into the charge material or into contact with a conductive crucible.
It is important to check your furnace’s ground leak detector probe frequently because it can be covered during improper furnace relining, can burn off, canbe isolated by slag, or otherwise canbe prevented from providing a sound electrical ground. This check canbedone with Inductotherm’s ground leak probetesting device an easy-to-use, hand-held device for verifying your furnace’s ground connection. Itcanbe used with any system equipped with a ground leak detector probe. Failure to insure that the grouno leak detector probe wires provide a sound ground contact will result in the loss of protection for the operator and furnace provided by the ground leak detector system.
System Maintenance Module
Your ground detector module shouldbe checked at least daily by pushing the test button on the ground detector module. This will indicate if the module’s electronics are working properly. Not that some residual leakage to ground,in the one to two milliampere range, is normal. In fact,if less than 1 milliampere is shown, it may indicate that the ground detector is not properly connected to the induction coil. Contact Inductotherm service department for further information safety.
Because of the crucial safety functions ground leak detection systems have in coreless induction melting and holding, your furnace should not be operated without a fully functional ground leak detection system.
Operators and maintenance staff working with Inductotherm quipment should take careful note of an urgent safety hazard ssociated with oil seals and “O” rings made of a substance called VITON, VITON seals are used in Inductotherm equipment and we want you to be aware of a potential problem which was recently recently brought to our attention.
While safe under designed operating conditions, VITON has been found to decompose into dangerous hydrofluoric acid if exposed to high temperature. Hydraulic acid is extremely_corrosive and almost impossible to remove,particularly from human tissue.
Viton Seal Safety Advisory
When inspecting equipment which has been exposed to a high temperature, check of any gaskets have suffered from decomposition. These will appear as a charred or black sticky mess.
You must not, under any circumstances, touch either the seal or the equipment until a substantial cooling period has been allowed and the equipment has been decontaminated.
Disposable, heavy-duty plastic gloves approved to withstand contact with hydrofluoric acid, safety glasses and a face shield should be worn and the affected are should be cleaned using wire wool and a detergent solution. The gloves must be safely discarded immediately after use.
The ground leak detector probe on Inductotherm furnaces (except removable crucible furnaces), is an important safety device. It provides an electrical ground on the molten metal bath which is designed to work with the ground leak detector to shut down the unit if molten metal touches the energized coil. This is crucial to furnace operator safety because if the moltenbath or furnace charge is not grounded via the ground leak detector probe, the power supply will continue to run even with molten metal touching the coil. As a result high voltage would be carried by the molten bath or furnace charge and could cause serious or even fatal electrical shock to the operator when slagging, taking samples or measuring temperature.
Ground Leak Detector Probe Safety Advisory
Care must be taken when installing a furnace lining to insure that the ground leak detector probe wires come into contact with the lining former.
Also, when patching a furnace lining, it is essential that the ground leak detector probe wires remain in contact with the furnace charge material.
If the wires are too short, extra lengths of 304 stainless steel wire should be welded to the existing wires to extend the wires into the charge material.
Failure to insure that the ground leak detector probe wires are in contact with the furnace charge will result in the loss of operator and furnace protection p and could lead to injury or death. rovided by the ground leak detection system
Continuity from the furnace bath to ground should be checked daily to insure that the molten metal is grounded.
Check with the Inductotherm Service department to verify the specific ground lead detector probe continuity checking procedures for your particular unit. If you find the bath is not grounded, the for y furnace must not be energized.